Details

A page view for columns allows a single url to be associated with the
tasks in a column. This helps a variety of use cases along the lines
of "please go look at this" instead of "go to the board and here are
the instructions for what I want you to look at".

It also allows batch actions to be taken on the tasks in the column.
For example closing all of the 'Done' tasks, commenting on all the
'Needs Info' ones, or adding another project (ie bumping them to the
next sprint). However, it dodges all of the complications of
arbitrarily complicated search predicates (you can only "search" for
one column in one board at a time). This will also support ad-hoc
actions after the task has been moved but before a relevant T5474
trigger existed.

Test Plan

View a workboard and see that nothing has regressed.

Click on the title of each column to open it up in a new window.

Verify that the right tasks show up and they are sorted as they were in the board.

Switch sort type and see tasks re-sort.

View each canned filter and see the right columns displayed.

Create an advanced filter and verify results.

Copy and paste the url with a query key and verify the correct page.

Select a bunch of tasks and batch edit them to add a comment. Confirm a conment is actually added.

This "basically works" but needs a *a lot* of work and has a bunch of
issues to resolve.

Guidance Needed:

There is a bunch of copy and paste code which is not the greatest. Inheriting from PhabricatorProjectBoardController seemed neither good nor how idiomatic (it's final after all). There may still be some un-needed cargo cult code.

Getting some of the outstanding problems fixed will probably involve changes to ManiphestTaskResultListView which I didn't want to do unless this was on the right track. Re-using ManiphestTaskResultListView seems like the right thing to do but it's a bit wonky.

I think I mostly got the style right, or at least arc lint seems happy, but emacs has been disinclined to indent like this so I could have done something icky.

Current issues:

changing order in column view does not really change natural sort order, probably best do dissallow but need the tasks to be 'selectable' for ManiphestTaskResultListView.

filters from the board are not retained when clicking on individual columns.

batch edit takes you to a maniphest page, which may or may not be good

advanced filter causes cards to be grouped by priority

dummp text needed to keep menu buttons from being cut off

something inconsistent problems with selecting individual gripable tickets. Select all works but selecting individual ones does not. I'm having the same issue on other vanilla phabricator installs such as this one so I'm confused.